The examples you've used aren't ATG so I'm not sure what your criterior is.
Passed greats can loose a decs. when their at their end (prime) or in their youth but as someone mentioned if they've already attained greatness then their the ones who hang around to long will loose some bouts, its the course.
Sugar Ray lost a few decs to Harrington at the end of his career, nobody cares. Ray got to go to Hawaii for few months and had a great time other than fighting that crazy southpaw!!!

Young fans place WAY to MUCH emphasis on losses, I guess because of Mayweather but Mayweather has maintained his record by avoiding high caliber opponents. Not exactly the way to maintain a undefeated record!

Ray

Weeell, it IS actually the way to maintain an undefeated record. You may not recall, because writing habits change, and writers change, but the analysts and writers some years ago always used to mentions Mayweather's "Brains Trust" (probably meaning his father and uncles, and maybe one other) who carefully selected his opponents, to give his the maximum advantage, with the least possible risk. Oscar's matchup guys also used to be called his "Brains Trust".

But, as I say, people and writers have changed and nobody remembers this.